Something I notice about a lot of hints here is that they recommend system-wide configuration changes when a per-user configuration change is good enough. Having system wide defaults is good, but the user should be able to change from the default without too much trouble.

As such, it is helpful to know that all the files that appear in a new user's account come from the /System -> Library -> User Template directory. If you add files to one of the *.lproj directories there, then those files will be copied to any new user's home directory when it is created.

This brings me to the second part of my hint, which has been prompted by all the X11 hints about setting the DISPLAY environment to get X11 forwarding to work nicely with the Terminal.

Most previous hints have been to do the standard UNIX thing by adding a setenv DISPLAY ... line to /etc/csh.cshrc. This works, but the envrionment changes are only available to processes that source /etc/csh.cshrc, ie csh or tcsh. Instead, you can have the enviroment set for all process that you run if you follow Apple's instructions for Setting environment variables for user processes.

RCEnvironment is a Mac OS X 10.1 or higher preference pane that allows a user to edit their ~/.MacOSX/environment.plist file. This file is simply a property list of keys and values that the login system will read and load into the process environment of all applications that are launched when the user logs in. These variables are the same as environment variables that can be created in a command line shell (eg: sh or csh), but they also can be seen by GUI applications. In this, these environment variables are somewhat similar to Windows' Environment User Variables.